The method of distinguishing the natural fallen leaves of potted orchids from those caused by diseases

First, natural fallen leaves

The new buds of orchids need a lot of nutrients, and some old leaves will "sacrifice" themselves to transfer their stored nutrients to the new buds. The characteristics of fallen leaves caused by this metabolism are mainly as follows:

1. The leaves will turn yellow very quickly, and it usually takes only a few days from discovery to full yellowing.

2. There is no obvious boundary between yellow and green in orchid leaves.

3. When the leaves turn yellow, there are no symptoms of dehydration.

4. All the leaves are brown and dry at last. If you touch the leaf gently, the leaf will fall off naturally from the petiole.

5. The yellowing of orchid leaves generally occurs on the old leaves of old seedlings.

Second, fallen leaves with disease

1. Characteristics of fallen leaves caused by diseases.

The leaves are necrotic one by one, with obvious boundaries; the speed of necrosis is relatively slow; most of the fallen leaves caused by soft rot occur on the new seedlings, and the leaves lose their luster at first, then become dehydrated and withered, and then rise with a gentle pull, but not at the petiole.

2. The regularity of the disease

High temperature and humidity environment, plant hardening, poor ventilation, prone to this disease, serious orchid plants will cause dehydration, lack of nutrition and death.

3. Prevention and control methods

Timely treatment of orchid wound, orchid ramets immediately apply wound healing agent or broad-spectrum fungicide to prevent infection.

It was found that the diseased seedlings were cut off and destroyed in time, and all the plant materials and orchid pots used by the diseased seedlings were abandoned and replaced with new plant materials and orchid pots.

When raising orchids, it is necessary to ensure that the culture environment is well ventilated, and orchid pots should not be placed too dense.

During the peak period of the disease, the plant around the diseased plant should be protected by spraying its root neck with medicine every 15 days. The main control agents are 80-1000 times of 75% dimethanesulfonate soluble powder, 8-1000 times of 25% prochloraz EC, and 80 times of 70% dimethrin wettable powder.